So, it's finally here - or should I say they - the family of Apple iPads has arrived. For the first time in what was beginning to feel like an age, Steve Jobs reached into his magic hat and pulled out a completely new device for us all to marvel at, upon and about. Yes, the tablet looks hot. It was always going to. Yes, it's also desirable but it could have been a white painted plank of wood with an Apple logo burnt into it and there would still be a voice deep within everyone's soul crying out to own.

But before we get carried away any further on this Apple-powered tablet wave, just to blow the Jobs-induced high one second - is what we've seen today really that much more necessary than a trusty old iPod touch, a smaller tablet we already know? Sure, it's slinkier and more specced-up but does it make enough of a difference? Is it really worth the extra $400 and which is the one your life really needs? Let's compare the two on a few key functions and stats.

The first thing to say here is that you can read newspapers, magazines, websites, ebooks and all sorts of literature on both the touch and the iPad. The key here is, how much of that do you intend to do? The advantage, of course with the iPad is that it's got the iBook store but there's no reason to believe so far that these files aren't transferable to the smaller devices or indeed that you definitely can't access this app from the touch. After all, it is an app you find in the App Store.

Other than that it's the bigger screen size that's the major plus point. The larger display is great for getting more copy on. That said, it's not e-paper or e-ink and still uses a backlit display that'll hurt your eyes a lot more than modern eReaders. If you're really planning to use this kind of device for books, then it's only better than a laptop by virtue of not having a keyboard attached to it. Want novels and newspapers and it's probably a Kindle you're after.

What's more, there was no mention of the battery life when being used as a reader. That blaring display - even if it's LED technology - is no match for the thousands of page turns you get out of one charge of a reader.

If music is what you're after, then there's just no point going with the tablet - nice as it is. iTunes and Apple pods are such that ultimately they all offer the same basic functionality. They all have the dock port and, as such, you can strap them to just about any larger audio playing device you like if you want your music played through a better speaker set.

Perhaps the one advantage of the tablet is that it's got a better on-board output than the touch. There's reference to built-in speakers plural rather than just the one although confirmation is required. If so, that would be important if you want to continue listening to music on the device in a room, which doesn't have an audio set up and you also don't want to be tied to your player by heaphones cable. That might sound rather specific but think of doing the washing up or ironing or other such scenes of domestic bliss while streaming Spotify onto your device.

Also, and this is one of emotion rather than anything else, the iTunes LP feature, as released in the latest incarnation of the Apple music software, would actually work really well on the iPad. Reading all those lyrics and looking at the album art with a large flat piece of hardware in your hands is rather reminiscent of old vinyl albums. Could the iPad be the LP for the 21st century?

On the other hand, that's got to be out-weighed by the fact that you can then stick the iPod touch into your pocket and go out to work. With the tablet, you'd need a pretty capacious suit lining.

Obviously, both these machines can play video. Now, your initial reaction to the specs on the tablet might be that it's much better for watching video, well, actually, you'd be right but not quite as right as the knee jerk reaction might lead us to believe. Yes the tablet's screen has the advantage of being LED backlit, better resolution - 320 x 480 vs 1024 x 768 - and bigger as well, but let's just debunk some of this a little for a moment.

Bigger is only relative to how far away from your eyes you hold it. The tablet is a lot heavier than the touch and maybe not as comfortable for the length of an entire feature film. Of course, there's bound to be all sorts of stands and accessories to help out but you could always stick with the touch at around chest height instead. Perhaps not entirely practical but certainly a solution for those who're not that interested in watching video on their portable device. After all, if you're at home, you could always just switch on the TV instead and, if out an about, you might rather stick with the lighter option.

On the LED side of things you can't really mess with that. It'll have better localised dimming for a cleaner picture and it'll also be far kinder on the battery than a standard LCD. You get 10 hours use out of it, we're told. However, the better resolution doesn't necessarily make it a better display. The fact that the iPad has XGA resolution just means it's got more pixels, but then, it's a bigger screen, so it needs to have more pixels not to look rubbish. The 3.5-inch LCD on the iPod touch may only be 320 x 480 but it has a higher pixel density - 163ppi vs 132ppi - and that's what gives it the added richness.

The launch of the App Store has put a huge focus on gaming but, as good as the touch has been for the purpose with its graphics hardware and accelerometer control, there has always been something missing in terms of using your thumbs. There was initial speculation that the iPad would offer some kind of dual thumb control but it seems that never happened. As such, the only real advantage it seems to offer over the touch is, again, the bigger screen and processor power.

Let's ignore the fact that the majority of the current games will only play in a tiny 1:1 resolution box or in poor resolution "pixel double" mode. A good body of specially tailored games will arrive soon. The real issue is that the iPad is still unlikely to replace the likes of the PSP and the Nintendo DSi XL on the move and will certainly pale into insignificance compared to gaming choices in the home. Still at least you'll be able to see the cards clearly in a game of patience.

Well, here's one area where these two things are entirely identical. Both are screaming out for cameras - one for photos and video and the other for web chat and conferencing - and neither has one. iPad 2G maybe? In the meantime iPad users will be able to import images via an Apple SD card reader or USB dongle for their camera. It will mean that this will be perfect for those that want to ditch the computer for their imaging needs altogether. 

For pure portability, the smaller of these two is the most portable. Yes, it's an obvious one but easily overlooked when blinded by gadget lust. If you're really after something for all occasions, then go for the iPod touch. The iPad is good for the home and great for plane journeys or anywhere you're happy to take a large bag but it's not something to stick in your pocket. Just make sure you ask yourself what you're buying this product for.

The addition of the iWork app for $9.99 has rather shown the iPad off for what it is - the netbook compromise that Apple never wanted to make. As it goes, it's a lovely compromise. It's a powerful, slick device and this is certainly an area where the iPod touch cannot compete. Office apps for the small screen just won't cut it and the tiny touch keyboard is useless compared to either the soft or hard option on the iPad. Just imagine rolling into a sales pitch with this instead of that 10-year-old laptop. It just doesn't compare does it?

It's hard to see that Apple has created a new kind of device here rather than just an iPod touch XL. It's certainly an alternative form factor but it's highly debatable as to whether there really is a viable space between the laptop and the pocket portable media player/smartphone for the majority of users.

Working on the iPad doesn't look as easy or flexible as doing so on a MacBook and the leisure uses don't really seem that far in excess of the iPod touch or iPhone either. In the home, it'll have to fight against the laptop, desktop or TV and on the move it's either a laptop or pocket portable solution once again.

If you had an iPhone/iPod touch, an iPad and a MacBook sitting on the table and you were about to leave the house, when would you choose to take the tablet? A long plane journey or a business meeting perhaps? Hard to tell. When it comes down to it, the proof of the pudding will be in the eating and we'll just have to wait for it to make it into the home to see how it performs and what its use will be to know if there's really been an iPad-shaped hole in our lives all along.

Full iPad specs